This invention relates to fluid brake control systems, and while the invention is subject to a wide range of applications, a preferred embodiment of the invention will be particularly described as applied to a fluid brake control system having a control valve in which the emergency portion has an improved cover.
The present invention is an improvement over currently used quick service control devices of the well-known ABD control valve generally used for governing the brakes of freight cars. The term "quick service" as used herein relates to apparatus and systems associated with respective freight cars of a train for incrementally reducing pressure in the brake pipe locally in response to sensing that there has been a reduction in brake pipe pressure independent of the local apparatus. This provides for quicker and smoother braking by increasing the rate of propagation of a service braking signal throughout the train.
In the ABD valve, a form of quick service function is provided by the service slide valve, but to provide repeated quick service cycles as long as the brake pipe pressure continues to be reduced, the ABD valve must be supplemented by a special quick service control device such as the well-known B1 quick service valve or the special quick service valve disclosed in the U.S. Wilson et al U.S. Pat. No. 3,716,276. The type B1 quick service valve is separate from the ABD valve and requires a separate pipe bracket including a separate quick action chamber and other devices.
An object of the present invention is to provide a fluid brake control system having improved quick service control which substantially obviates one or more of the limitations and disadvantages of the described prior systems.
Another object of the present invention is to reduce the number of control devices required to provide the function of quick service controls.
Another object of the present invention is to reduce manufacturing and maintenance cost of brake application control devices.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description of the invention progresses.